Kaiju Slayer

Unfortunately, the Python bike upgrade is available only to those that funded during the M3 milestone.

However, if you were to win an M3 pack during one of the Chief Chat giveaways on Discord, or are gifted one, you will be eligible for an upgrade/purchase of the Python bike. I suggest keeping an eye out for these.

EDIT: A Chief Chat has been announced for the 30th of this month. You could try your luck during the event on Discord.